Networks for wireless communication are typically surveyed and operated by means of a central management system which, depending on the standards and terminology used, may be referred to as, e.g. “Operation Support System” (OSS), “Network manager” or “Domain manager”, the latter term being used by the Third Generation Partnership Project (3GPP). The general term “management system” will be used in this description to represent any system, function or centre that handles the network e.g. in terms of Operation and Maintenance (O&M). Further, the term “cell controlling node” will be used to represent any radio node in the network that can provide radio communication for User Equipments (UEs) in a cell. Depending on the standards and terminology used, the cell controlling node in this context may thus be a base station, a Node B, an evolved Node B (eNode B), a Radio Network Controller (RNC), a Radio Base Station (RBS), and so forth.
In order to monitor performance, alarms, quality and end-user experience in the network, cell controlling nodes such as base stations in the network frequently send performance related reports to the management system which may refer to e.g. measured performance data, throughput, latency, resource usage, error rates, and so forth. The management system thus generally monitors the performance in the network based on such reports in order to detect any problems and shortcomings in the network, and to correct or otherwise deal with these problems and shortcomings.
Today, the management system handles such performance related issues on a cell or base station basis which has traditionally been suitable for networks with well-defined and separated geographical areas for the cells. However, in order to meet the demands of increasingly advanced UEs and services of today, the modern networks for wireless communication are becoming more and more heterogeneous in the sense that cells of different sizes and overlapping radio coverage areas are added to the networks to meet the increasing demands. For example, in an area covered by a relatively large cell, or “macro-cell”, it may be necessary to add a number of smaller cells, e.g. so-called “micro-cells”, pico-cells”, nano-cells and “femto-cells” to provide increased data throughput in small areas such as hotspots or the like.
An illustrative example of such a heterogeneous network for wireless communication is schematically shown in FIG. 1 where a macro-cell A provides a relatively large radio coverage area. Further, two micro-cells B and C provide more limited coverage areas within cell A, and a number of even smaller cells D-H with coverage areas within cell A, e.g. pico-cell, nano-cells or femto-cells depending on the terminology used have also been added to the network. In this example, the coverage areas of cells G and H are further overlapping with cell C as well.
For example, a UE located in a certain area may be connected to a macro-cell or alternatively to a micro-cell or femto-cell, etc., depending on how the network allocates its resources at the moment and decides which base station or cell controlling node to serve the UE. As a result, a corresponding performance related report pertaining to the UE in this area can be quite different depending on whether it is sent from a macro-cell, micro-cell or pico-cell, etc., and the evaluation of performance in a certain area may be highly dependent on which cell controlling node has provided the performance related report. It is thus a problem that the performance related reports for a certain area are different depending on which cell controlling nodes have sent the reports, and that it may be laborious in the management system to determine which reports are valid for that area particularly when the coverage of the cells and configuration in base stations and cell controlling nodes often changes.
Furthermore, a heterogeneous network for wireless communication of today may comprise a huge number of cells of different types and sizes, frequently with more or less overlapping coverage areas, where performance related reports are provided separately for each cell to the management system with different cell identities. It is also a problem that the task of evaluating the performance and finding faults can be quite complex when so many cells are involved, making great demands on the management system's capacity and resources. This problem becomes ever more accentuated when the network is changed from time to time, e.g. by adding, modifying or removing cells.